Hydraulic checking device for looms



FIG. 2.

DECELERATION PLUNGER RETURN L jsLSTANCE I INVENTOR. NEVIN S. Foam? F IG. 4. FORCE LEVER DIAGRAM suu'r'ruz. 1=1c1 1-:R sncn nncrzxmmnqu BUFFER RESISTANCE BY i HATWH IN BUFFER RELATIONSHIP DECELERATlON OF SHUTTLE FORCE STROKE FIG. 3

s o MAXIMUM Nov. 3, 1964 MAXIMUM United States Patent 3,155,120 HYDRAULIC CHECKING DEVICE FOR LOOMS Nevin S. Focht, 179 Washington Ave., Garden City, Long Island, N.Y.; Georgeana L. Focht, executrix of said Nevin S. Focht, deceased Filed Feb. 27, 1962, Ser. No. 175,962 6 Claims. (Cl. 139161) This invention relates to a hydraulic checking device for looms and more particularly to an improved hydraulic check device for controlling the movements of the picker sticks of a loom.

As is well known, effective control of the picker stick is one of the most dimcult problems in connection with the operation of a loom, and one which heretofore has not been solved satisfactorily. Many attempts have been made in the past to provide an eifective checking device, but these attempts have not met with any great degree of success, and the ordinary leather check strap is still very Widely used, although there are numerous obvious disadvantages to this method.

Several attempts have been made to provide a form of hydraulic checking device, but these prior devices have been found subject to numerous shortcomings and have proven generally unsatisfactory for continuous high speed operation. In particular, these prior devices have failed because they were attached to the picker stick by means of links and bearings, which proved to be subject to rapid wear over long and sustained periods of operation, resulting in a loss of motion and infiective checking of the picker stick. Another objection was that changes were required in the loom mechanism, and it was usually necessary to shut down the loom for a considerable period of time for the purpose of installing or repairing the mechanism.

It is, therefore, an object of this invention to provide a hydraulic check device for a loom which eliminates previous difliculties and which will effectively and satisfactorily control the checking of the picker stick over long periods of operation.

It is a further object of this invention to provide a picker stick checking device which may be quickly and easily adjusted for checking force while the loom is in operation.

A still further object of this invention is to provide a device which may be readily adapted to various types of looms.

The invention has a still further object of providing a checking device which eliminates bearings and linkages and will give long wear and trouble-free operation even when operated at higher speeds than are now customary, eliminating down time formerly required for adjustment and replacement of check-straps, thus resulting in less maintenance and greater production.

A further object of the invention is to provide a checking device wherein better boxing of the shuttle is attained and sloughing is greatly minimized, resulting in a better quality of cloth and reducing the chance of seconds.

These and other advantages of the present invention will become more readily apparent from the following description, in which reference is made to the accompanying drawings, wherein:

FIGURE 1 is a sectional view of a hydraulic checking device.

FIGURE 2 is a side view of a conventional loom mechanism showing the mounting of the device;

FIGURE 3 is a force diagnam showing the relation between the shuttle velocity and stroke of the picker stick.

FIGURE 4 is a force-leverage diagram.

Referring now to FIGURE 1, the hydraulic checking device comprises a cylindrical outer casing 1 closed at one ice end by means of an end wall 2 and having a piston cylinder 3 slidably disposed within the casing adjacent the opposite open end. The piston cylinder 3 has an inwardly facing chamber which is closed by a cylinder head 3 and piston rod guide 4. A neck-like portion 5 of the piston cylinder extends outwardly from the casing and terminates in a mushroom shaped contact bumper 6. The contact bumper may contain a projecting insert 7 of a relatively elastic substance such as nylon. The piston cylinder 3 has disposed within itself a metering pin 8 adapted to move within a bore in a piston 9, slidably disposed within said piston cylinder. A hollow piston rod 10 is provided with an O-ring seal 11 in a fixed reservoir base 12, and is secured at one end to the casing end wall 2 by a sealing locknut 13. The piston cylinder 3 is held within the casing by a snap ring mounted in the casing adjacent the open end thereof. The piston 9 mounted on the free end of hollow piston rod 1% divides the piston cylinder 3 into two fluid pressure chambers 15 and 16 on opposite faces thereof, these chambers being filled with oil or other suitable non-compressible fluid. A chamber 17 formed between the reservoir base 12 and end wall 2 acts as a reservoir and contains an additional amount of fluid which replenishes the fluid in chambers 15 and 16 by way of ports 18 in the upper end of the hollow rod 10 and a valve 19 at the lower end of the rod 10 within the piston cylinder. Replenishing valve 19 is held in position by a spring 20 which urges the base 19 of the valve upwardly to a normally closed position when the piston cylinder 3 is at rest or moving inwardly or upwardly, so that fluid in the chamber 16 cannot enter reservoir 17 through the hollow rod 10, but is forced into chamber 15 by way of metering pin groove 21 through which the metering pin 8 passes.

Valve 19 is provided at its upper end with an enlarged head 19 slidably disposed within the hollow rod 10. The purpose of the head 19 is two-fold. First, it provides centering or alignment means for the conical face 19 of the valve in order to insure a fluid-tight fit between the face 19 and base of the rod 10 when the valve is in the position shown in FIG. 1. Secondly, the bead 19 provides the control means to regulate the passage of fluid through ports 41 as described hereinafter. It will be understood that the sliding fit existing between the head 19 and inner wall of rod 10 permits the passage of fluid under pressure therebetween.

As cylinder 3 rises in casing 1, the air in the space between the fixed reservoir base 12 and rod guide 4 will be compressed. A rubber tube 22 surrounds a hollow stand pipe 23 mounted within the reservoir 17 and resiliently covers a valve seat 24. The compressed air will stretch the tube 22 off seat 24 admitting the compressed air to the reservoir chamber 17 by way of the hollow stand pipe 23. Replenishing of the pressure chamber under the fast action of the buffer is thus further assured because the replenishing fluid is always under pressure above atmosphere. On the downstroke of the piston cylinder 3, the rubber tube at 24 takes its seat and air enters the above mentioned space through the pipe 23 by way of an air-vent valve 25 and port 26 leading to the pipe 23 through the end wall 2. Some air escapes between the cylindrical clearance of case 1 and cylinder 3 and thus cools the cylinder. The reservoir 17 always remains stationary with reference to the plunger movement.

FIGURE 2 is a side view of a conventional loom mechanism showing the hydraulic checking device generally designated A, mounted in position on the rocker shaft 27 of a loom by means of an L-shaped bracket 28. The picker stick is shown at 29. Pick arm 30, operated by a convention loom mechanism, moves the stick 29 on a power stroke to throw the shuttle 31. The picker stick itself is mounted in a shoe 32 which has a curved parallel surface 33 rolling on supporting plate or parallel foot 34. Picker stick spring return, generally indicated as 35, is mounted in the well-known manner. In accordance with conventional practice, a race 35 is provided on the lay for the shuttle 31, and a picker 37 on the picker stick 29, throws the shuttle across the loom when the stick is advanced on the power stroke. The bracket 28 is clamped on the rocker shaft over the end of the parallel foot 34. The other end of the bracket clamps the hydraulic checking device A in operating position above the curved surface 33 of the parallel shoe 32. A spring lever 38 is pivoted at its middle and mounted upon a fixed shaft 39 disposed adjacent the shoe 32. This lever 38 has a forked end which extends outwardly and straddles the hydraulic cylinder A and contacts the top of the mushroom rim 6 of cylinder 3. The other ends of this lever contact the parallel shoe 32 by means of contact rollers 4i) riding upon the curved parallel surfaces 33. During the power stroke of the picker stick, the foregoing acts as a return means for the hydraulic plunger, and as a snubber for the picker stick after the shuttle has been thrown. Note force-leverage diagram, FIG- URE 4.

The operation of the hydraulic device is as follows: During a shuttle checking cycle, the picker stick is driven back by the shuttle, and the heel of the shoe 32 new contacts the mushroom-shaped contact bumper 7. The piston cylinder 3 then moves upward within casing 1, forcing the fluid from chamber 16 through metering groove 21 into chamber 15. The volume of fluid displaced by the presence of the hollow rod in chamber 15, over that of chamber 16, passes into the reservoir 17 through the rod 19 via ports 41 disposed in the bottom of the rod 10 just below the normal level of the valve head 1%, the fluid passing upwardly through the nominal clearance between the head and the rod 10.

A high-pressure seal 42, formed of a lubricant impregnated material such as graphite impregnated plastic surrounds the rod 10 and is arranged to be seated in a chamber 43 formed between piston rod 10 and piston rod guide 4. A low pressure combined static and dynamic seal 44, formed of a relatively flexible material such as rubber or the like, is arranged beneath the high pressure seal 42 with a portion thereof extending out to the wall of the piston and forming a static seal, while a dynamic seal is formed at the piston rod, as shown in FIG- URE l. A packing back-up washer 45 secures the seal members 42 and 44 in operative position.

Since the metering pin groove 21 is tapered, it will form a gradually decreasing orifice area as the plunger is moved inwardly. This produces the desired force stroke curve shown in FIGURE 3, with the gradual deceleration of the shuttle to a stop as represented by the deceleration curve, resulting in a smooth stop without a sudden shock and bouncing of the shuttle. Ballcheck valve 46 produces a bias across the piston u and maintains the proper force relationship between shuttle checking force and the picker stick snubbing action mentioned above. The ball check valve 46 is of the one-way type whereupon during the checking stroke it will be seen that fluid will be forced upwardly around ball 46, which is retained by suitable means such as pin 46 into chamber 15. The fluid passes around valve 46 at a constant rate throughout the checking stroke while the smooth deceleration of the checking stroke is achieved by the action of the fluid that passes through the tapered groove 21. Without the by-pass valve as, the desired velocity/buffer relationship is not readily obtainable. Adjustment for the checkingaction may be made by turning the hollow adjusting rod 1%) and piston 9 up or down with relation to the tapered groove 21 of the metering pin. It will be obvious to one skilled in the art that the tapered groove of the metering pin may be varied to provide a wide range of checking action as well as the adjustment obtained by moving the piston down and narrowing the area of the opening with reference to the piston. A further adjustment may be obtained by moving the checking device up or down within bracket 28.

On the power stroke of the picker stick, after the shuttle is thrown across the lay, the plunger return lever 38 will move downward and contact the mushroom rim 6 of the plunger. This action will push the plunger downwardly against snap ring stop 14, decelerating the picker stick, and the device will then be ready for the next shuttle check.

As the plunger cylinder moves downward, chamber 15 decreases in volume, and fluid is forced into chamber 16 by way of the hollow groove 21 in the metering pin 8.

Ports 41 will be closed by the cylindrical head 19 of replenishing valve 19 as it moves downward to admit fluid from reservoir 17 into chamber 16 via ports 18 and the hollow adjusting rod 10. During the checking stroke, the air in chamber 17 has been compressed; therefore, when the cylinder starts down, fluid will be forced into chamber 16 by positive air pressure as well as being drawn downward by the receding piston cylinder which creates a negative pressure in chamber 16. In other words, as soon the power stroke begins, the reduced pressure in chamber 16 allows the valve 19 to slide downwardly under the influence of the pressurized fluid from the reservoir 17, against the force of spring arm 20. A shorter spring arm 20*, also mounted in the piston 9, acts as a stop for the conical face 19 of the valve to limit its downward movement. As the valve moves downwardly under the above influences, the ports 41 are closed by the head 19 and the pressurized fluid in the hollow rod Jill is forced between the head and rod down into chamber 16 in an amount sufiicient to replace that fluid which was displaced by the hollow rod 10 in chamber 15 during the checking stroke.

As may be seen, positive checking action is accomplished without the use of connecting links or bearings which may be subject to wear, as the checking device bears directly against the shoe 32 of the picker stick. Additionally, the shuttle is brought to a gradual deceleration because of the tapered groove 21 of the metering pin. This type of action is similar to the catching of a ball, where the catcher draws back on his arm as the ball enters the glove, bringing it to a stop.

It will, of course, be understood that various modifications may be made within a Wide range without departing from the spirit of the invention.

I claim:

1. A hydraulic checking apparatus comprising a cylindrical casing, a cylinder slidably disposed within said casing and having a contact bumper extending from one end of said casing, a hollow rod mounted within said casing at the end opposite said bumper and extending into said cylinder, a piston mounted on said rod within said cylinder and dividing said cylinder into a pair of separate chambers, a check valve disposed at the base of said hollow rod, said valve including means for preventing the upward flow of fluid from said chamber immediately below said piston, a fluid containing reservoir within said casing conneeted to said hollow rod and communicating therethrough with said chambers, a tapered groove metering pin mounted within said cylinder and a bore in said piston, said pin aligned within said bore, whereby when said cylinder moves in said casing said pin slides through said piston.

2. A hydraulic checking apparatus comprising, a cylindrical casing, a cylinder slidably mounted within said easing and having a contact bumper disposed outside of said casing, a hollow rod having adjustable means for attachment at one end to said casing and having its lower end extending into said cylinder, a piston having a bore mounted on the lower end of said rod in said cylinder, a metering pin having a tapered groove fixedly disposed in said cylinder and passing through said bore in said piston, a pair of valves through said piston, said valves operating to provide open passages in opposite directions to one another, said adjustable means on said rod including, a threaded portion longitudinally movable relative to said casing to selectively position said piston with respect to said metering pin within said cylinder, whereby, when force is applied to said bumper to move said cylinder into said casing, said metering pin slides through the bore in said piston.

3. In a loom having a lay, a shuttle, a picker stick mounted in a parallel shoe rolling on a parallel foot, a rocker shaft, a picker stick stop mechanism comprising, a bracket mounted on the rocker shaft over the end of the parallel foot, :1 double acting hydraulic checking device provided with a contact bumper and supported by said bracket over said shoe, said contact bumper being of mushroom shape with the top surface thereof substantial- 1y flat, said hydraulic checking device disposed so that during a shuttle check the picker stick shoe bears against the bottom of said contact bumper, and a spring lever pivotally attached to said shoe and having a portion extending over and in contact with the flat top surface of said bumper, whereby, said spring lever provides connecting means to permit said hydraulic checking device to dampen a stroke of the picker stick during the power stroke.

4. A hydraulic checking apparatus comprising a cylindrical casing, a cylinder slidably disposed within said casing, a hollow rod mounted within said casing and extending into said cylinder, a piston mounted on said rod within said cylinder, a pair of chambers formed immediately above and below said piston within said cylinder, a fluid containing reservoir connected to said hollow rod and communicating with said chambers, and a check valve disposed at the base of said hollow rod, said valve including means for preventing the upward flow of fluid from said chamber immediately below said piston.

5. A hydraulic checking apparatus comprising a cylindrical casing, a cylinder slidably disposed within said casing, a hollow rod mounted within said casing and extending into said cylinder, a piston mounted on said rod within said cylinder, a pair of chambers formed immediately above and below said piston within said cylinder, a fluid containing reservoir connected to said hollow rod and communicating with said chambers, ports in said rod in said reservoir, an air chamber between said cylinder and said reservoir, a stand pipe having a passage communicating with said air chamber and reservoir, valve means on said pipe, whereby, movement of said cylinder towards said reservoir forces air from said air chamber into said reservoir to force fluid from the reservoir into said rod through said ports.

6. A hydraulic checking apparatus comprising, a cylinder, fluid within said cylinder, a piston in said cylinder moving against said fluid, a piston rod coupled to said piston and extending from said cylinder to permit shock loads to be transmitted to the piston, a piston rod guide having a bore through which said piston rod is mounted, said guide having a chamfer extending from the bore to its periphery, means resisting both dynamic and static forces formed between said piston rod and said cylinder to prevent the loss of fluid from said cylinder between both said guide and rod and said guide and cylinder, respectively, said means including; a lubricant impregnated sealing material in said chamfer adjacent to said piston rod to facilitate movement of said rod, a flexible seal extending from said rod adjacent said lubricated sealing material to said cylinder whereby the juxtaposed surfaces of said seal and sealing material are disposed at an oblique angle to said rod, and rigid backup means coextensive with the surface of said seal opposite said sealing material, wherein, said seal is disposed at an oblique angle adjacent said rod and maintained in sealing engagement with said rod by the compressive force of said sealing material and backup means on opposite sides thereof.

References Cited in the file of this patent UNITED STATES PATENTS 2,263,923 Hoeber et al Nov. 25, 1941 2,490,301 Higginson Dec. 6, 1949 2,589,282 OConnor et a1. Mar. 18, 1952 2,765,877 Carbon Oct. 9, 1956 2,812,717 Brown Nov. 12, 1957 2,916,106 Duckett et a1. Dec. 8, 1959 3,004,783 Webb Oct. 17, 1961 3,033,384 Zanow et a1. May 8, 1962 FOREIGN PATENTS 1,015,327 Germany Jan. 27, 1955 296,897 Great Britain Sept. 13, 1928 

1. A HYDRAULIC CHECKING APPARATUS COMPRISING A CYLINDRICAL CASING, A CYLINDER SLIDABLY DISPOSED WITHIN SAID CAS ING AND HAVING A CONTACT BUMPER EXTENDING FROM ONE END OF SAID CASING, A HOLLOW ROD MOUNTED WITHIN SAID CASING AT THE END OPPOSITE SAID BUMPER AND EXTENDING INTO SAID CYLINDER, A PISTON MOUNTED ON SAID ROD WITHIN SAID CYLINDER AND DIVIDING SAID CYLINDER INTO A PAIR OF SEPARATE CHAMBERS, A CHECK VALVE DISPOSED AT THE BASE OF SAID HOLLOW ROD, SAID VALVE INCLUDING MEANS FOR PREVENTING THE UPWARD FLOW OF FLUID FROM SAID CHAMBER IMMEDIATELY BELOW SAID PISTON, A FLUID CONTAINING RESERVIOR WITHIN SAID CASING CONNECTED TO SAID HOLLOW ROD AND COMMUNICATING THERETHROUGH WITH SAID CHAMBERS, A TAPERED GROOVE METERING PIN MOUNTED WITHIN SAID CYLINDER AND A BORE IN SAID PISTON, SAID PIN ALIGNED WITHIN SAID BORE, WHEREBY WHEN SAID CYLINDER MOVES IN SAID CASING SAID PIN SLIDES THROUGH SAID PISTON. 